November 10-15

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ACR Convergence 2023

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Experts to consider diagnostic dilemmas in myositis


5 minutes

When treating patients with myositis, rheumatologists must be cognizant of several considerations that could have severe — even fatal — consequences if left untreated.

The 90-minute clinical symposium Hot Topics in Myositis, starting at 4:30 pm Tuesday in Room 20 D, will provide a thorough review of these serious issues.

Asymptomatic HyperCKemia

Rohit Aggarwal, MD, MS, Associate Professor of Medicine and Medical Director of the Arthritis and Autoimmunity Center at the University of Pittsburgh, Pittsburgh, PA, will share pragmatic strategies for a patient who presents with elevated CPK levels but without symptoms or with only minimal symptoms during his lecture.

“Asymptomatic hyperCKemia poses a major diagnostic challenge for rheumatologists,” Dr. Aggarwal said. “As a result, many patients undergo invasive testing and are over-diagnosed or over-managed.”

Dr. Aggarwal said the core of this problem begins with measuring CPK in the lab. Many normal CPK levels are reported as abnormal because the norms being used are outdated and do not reflect the current literature. He’ll review evidence that demonstrates that laboratories often label likely normal CPK levels as abnormal, and he’ll discuss additional literature that shows CPK levels are highly dependent on gender and ethnicity, which current lab practices do not take into account.

Dr. Aggarwal will also outline practical strategies for clinicians, including when to start a diagnostic workup and what that workup should include.

“There are some cases where it would make sense to investigate, but in most cases, the patient needs reassurance rather than a workup,” he said. “There’s a good body of evidence that tells us what to do — it’s just not widely recognized.”

His talk will focus on that evidence to give rheumatologists a practical approach to asymptomatic patients with elevated CPK levels.

“There are times when investigation — including invasive investigation such as muscle biopsy — may be considered,” Dr. Aggarwal said. “But that decision needs to be made between the patient and the doctor. The patient must understand there may not be any treatment options available, even if you have a conclusive diagnosis. And the patient should know they may not require treatment. If you’re asymptomatic and your prognosis is excellent, why do you need treatment?”

Necrotizing Myopathy

Eleni Tiniakou, MD
Eleni Tiniakou, MD

Eleni Tiniakou, MD, Instructor of Medicine at Johns Hopkins University School of Medicine, Baltimore, MD, will give attendees an update on the recent literature on immune-mediated necrotizing myopathy (IMNM), which is now known to be more common than previously recognized. Until recently, just two major forms of autoimmune myositis were recognized: Dermatomyositis and polymyositis. In the past decade, IMNM has emerged as a distinct form of myositis that is more common than polymyositis in adults.

Dr. Tiniakou will discuss two antibodies associated with this type of myositis, SRP and HMGCR, and how to use these biomarkers to distinguish IMNM from other possible problems such as antisythetase syndrome, toxins, or cancer. She will also review recent data on the genetic risk factors and treatment of IMNM.

“There are some new considerations that have come to light, such as certain environmental factors, genetic risk factors, cancer risk, and different presentations in different ethnic groups around the world, which can have an impact on ideal treatment strategies,” she said. “There is a gap in knowledge regarding how to efficiently diagnose and effectively treat IMNM.”

She will also talk about this type of myopathy in children.

“We’re seeing more and more children previously diagnosed with untreatable genetic conditions who have been found to have myopathy,” Dr. Tiniakou said. “Many clinicians do not appreciate that IMNM also occurs in children, where this treatable form of myositis may be misdiagnosed as a muscular dystrophy.”

Interstitial Lung Disease

Paul F. Dellaripa, MD
Paul F. Dellaripa, MD

Paul F. Dellaripa, MD, Associate Professor at Harvard Medical School, Boston, will address a common concern among rheumatologists when he talks about interstitial lung disease in myositis patients.

“A significant number of patients with myositis will develop interstitial lung disease, but we don’t always know who,” Dr. Dellaripa said. “And among those that do develop interstitial lung disease, how do we know who will progress and do poorly?”

Lung disease is a major source of morbidity and mortality, which makes it a chief concern when treating patients with myositis.

“Patients don’t die of muscle disease,” he said. “They die of lung disease. Obviously, being able to identify lung disease is very important.”

Dr. Dellaripa said there are identifiable factors that put people at higher risk for lung disease, including certain antibody profiles and certain demographics profiles. In addition, close evaluation of pulmonary function testing can be useful when following patients who either don’t have lung disease or who have early disease and may be at risk for progression.

His lecture also will cover emerging antibody profiles that will serve as markers for those at higher risk of lung disease.

“Specifically, I’ll highlight the antisynthetase antibody and the role of the MDA5 antibody in interstitial lung disease,” he said. “From a serologic standpoint, there are markers that when identified should prompt us to evaluate for ILD. These markers can alert us to ask the right questions and follow these patients more closely. Clinicians need this type of guidance to determine who is at high risk when it comes to the lung.”

Dr. Dellaripa will also review the role of CT scanning, pulmonary function testing, and other clinical findings that may offer clues as to which patients have worse disease or more aggressive disease.

“The take-away message is we are moving in a direction where we can examine all of the information we compile on a patient — including biomarkers, features on CT scan, physiological parameters, and demographic features — to create a composite risk assessment that allows us to recognize at-risk patients early, treat them appropriately, and prevent progression of disease.”